Alcohols and amines are useful compounds widely used in industrial applications, and therefore their production methods are important in industrial fields. An example of known methods for producing an alcohol or an amine is described in Reference Document 1 (Reductions by the Alumino-and Borohydrides in Organic Synthesis VCH Publishers, INC. 1991), in which an amide compound is reduced using a metal hydride. However, this method has problems such as the use of a dangerous metal hydride reagent and the generation of waste from the reagent theoretically required in an amount equal to or higher than that of the amide compound. For suchlike reason, there is a demand for a chemical synthesis technique that is more environmentally friendly and safer. An example of such a chemical synthesis method is the one in which alcohols or amines are catalytically produced from an amide compound under an atmosphere of hydrogen.
An example of a catalyst that catalyzes such a reaction is ruthenium complex. Along with platinum, rhodium, and iridium, the ruthenium complex is one of metals often used as a catalyst. However, the ruthenium complex is industrially advantageous in that it is cheaper than the other metals. An example of such a ruthenium complex is the one having a multidentate ligand. Patent Literature 1 discloses a dichloro complex as a ruthenium complex having a tridentate ligand containing two phosphino groups and a —NH— group, and Non-Patent Literature 1 discloses a dichloro complex or a hydride complex having trimethylphosphine as a ligand. However, these complexes have no carbonyl ligand. Further, Patent Literature 1 describes that the ruthenium dichloro complex catalyzes the hydrogenation reduction of ketones in the presence of a base so that an alcohol is obtained, but does not describe a method for obtaining an alcohol or an amine from an amide under an atmosphere of hydrogen. Non-Patent Literature 1 describes that the ruthenium phosphine complex acts as a catalyst for dehydrogenation of ammonia-borane, but does not describe a method for obtaining an alcohol or an amine from an amide under an atmosphere of hydrogen. Non-Patent Literatures 2, 3, and 4 disclose a ruthenium complex having a tridentate ligand containing two phosphino groups and a pyridine ring, and a carbonyl ligand, but this tridentate ligand does not contain a —NH— group. Further, it has been reported that the ruthenium phosphine complex used as a catalyst is unstable. Non-Patent Literatures 2 and 3 describe that alcohols can be synthesized by hydrogenation reduction of an ester with the pyridine ring-containing ruthenium complex as a catalyst, but do not describe a method for obtaining alcohols or amines from an amide under an atmosphere of hydrogen.
As methods for catalytically producing alcohols or amines from an amide under an atmosphere of hydrogen, methods described in Patent Literatures 2 and 3 and Non-Patent Literature 5 are known. However, the method described in Patent Literature 2 and the method described in Non-Patent Literature 5 are methods for obtaining an amine, and the structures of the amine obtained by these methods are different from the present invention. Even when an alcohol is produced, the alcohol is only obtained as a by-product or in a low yield. Patent Literature 3 discloses a cyclopentadienyl complex as a catalyst, but the cyclopentadienyl complex is different in structure from a catalyst used in the present invention. Further, the reaction time of about 24 to 90 hours and 1 to 10 mol % of a catalyst with respect to a substrate are required to achieve a sufficient conversion rate, except for cases where some substrates that achieve an exceptionally-high reaction rate are used.